This invention relates to a magnetic hard disk drive and a process for producing the same, more particularly, to a magnetic hard disk drive having loaded therein a magnetic disk and a magnetic head slider for preventing the start failure due to stiction between the magnetic head slider and the magnetic disk.
As a method for preventing the start failure of a magnetic hard disk drive due to the stiction, it is known to be effective to allow the magnetic disk-facing surface of the slider to have a low surface energy, thereby inhibiting the adhesion and buildup of a lubricant or grease onto the slider. That is to say, there is such a phenomenon that during the long term operation of the drive, the lubricant applied to the magnetic disk and the grease applied to a spindle bearing or a carriage bearing adhere to and build up on the slider and, after the stopping of the drive, they spread into the contact space between the slider and the magnetic disk to fill up the space, and consequently, a great adsorption force acts on between the slider and the magnetic disk by the meniscus force in the space, whereby the slider and the magnetic disk adhere to each other. It is the technique which intends to prevent, in this case, the buildup of the lubricant and grease on the slider by allowing the magnetic disk-facing surface of the slider to have a low surface energy, and consequently prevent the start failure.
As a prior technique for allowing the magnetic disk-facing surface of the slider to have a low surface energy, JP-A 63-64,684 discloses that a layer having a lower surface energy than that of the constituting material of the slider body, for example, a polytetrafluoroethylene (PTFE) layer is provided on the surface portion not contacting the magnetic disk on the magnetic disk-facing surface of the slider to which a magnetic head is attached.
However, according to the prior technique disclosed in JP-A 63-64,684, the magnetic disk-facing surface of the slider is composed of a PTFE layer having a low surface energy, and since the surface energy of PTFE is 15 mN/m, it has an effect of repelling the grease to prevent the grease from adhering to the slider. However, the surface is insufficient in ability to repel a lubricant for magnetic disk which lubricant has a surface energy as low as about 20 mN/m, and hence, there has been such a problem that it is difficult to prevent the lubricant from adhering to the slider and consequently prevent the start failure of the magnetic hard disk drive due to the stiction resulting from the lubricant.
From the above surface energy values of the PTFE and lubricant, it has been inferred that the contact angle of the lubricant on the magnetic disk-facing surface of the slider provided with the PTFE layer is about 40.degree. and, at such a low contact angle, the sufficient prevention of the lubricant from adhering to the slider is difficult.
On the other hand, in JP-A 54-58,736, a method is proposed which comprises treating the surface of a slider with an alkali and thereafter adhering thereto a material having a fluorinated alkyl group and a terminal halogen, cyano or alkoxyl group to form a low surface energy layer.
When the surface to be treated is treated with an alkali, it has an effect of enhancing the adherability of the above-mentioned material having a fluorinated alkyl group and a terminal halogen, cyano or alkoxyl group, but has such a disadvantage that the magnetic layer of the magnetic head existing at the back end of the slider is eroded. Moreover, when the surface of the slider is composed of a non-metal such as a carbonaceous material or the like, there has been such a problem that the above-mentioned terminal group hardly adheres and the stability thereof becomes very low.